Action Points

The risk of bleeding, stroke, and pump thrombosis after receipt of a continuous flow left ventricular assist device (CF-LVAD) differed by demographic group and was highest in women.

Note that the adverse event rate was higher for post-discharge bleeding than for hemorrhagic stroke, ischemic stroke, and pump thrombosis.

The risk of bleeding, stroke, and pump thrombosis after receipt of a continuous flow left ventricular assist device (CF-LVAD) differed by demographic group and was highest in women, a retrospective analysis reported.

Older age (>65) (Hazard Ratio=1.31), lower preoperative hematocrit (≤31) (HR=1.31), ischemic etiology (HR = 1.35), and female sex (HR=1.45) were statistically significant multivariable risk factors for bleeding, wrote Andrew Boyle, MD, of the Cleveland Clinic Florida, and his co-authors online in The Journal of the American College of Cardiology.

Being female (HR = 1.92) and age ≤ 65 (HR = 1.94) were multivariable risk factors for hemorrhagic stroke. Being female (HR = 1.84) and having a history of diabetes (HR = 1.99) were risk factors for ischemic stroke.

"I think the study's important in clinical care in that we are able to probably target subpopulations better," study co-author Soon Park, MD, of University Hospitals Case Medical Center in Cleveland, told MedPage Today.

"The striking finding is that female sex was a risk factor for all events," wrote Samer S. Najjar, MD, of the MedStar Washington Hospital Center, in an accompanying editorial.

"Importantly, women enrolled in the HeartMate II BTT clinical trial and in other LVAD studies have a similar survival to men," wrote Najjar. The higher event rate in women than men, even if confirmed in future studies, shouldn't dissuade use of CF-LVADs in women but rather "galvanize us to elucidate the causes," he said.

The adverse event rate was higher for post-discharge bleeding (0.67 events/pt-yr), than for hemorrhagic stroke (0.05), ischemic stroke (0.04), and pump thrombosis (0.03). The main sites of bleeding were gastrointestinal (45% of events), wound (12%) and epistaxis (4%).

The study was a retrospective analysis of 956 advanced heart failure patients who'd been discharged from the hospital after having a CF-LVAD implanted in the HeartMate II bridge to transplant or destination therapy clinical trials.

Details related to menopausal status and oral contraceptive use were unavailable to the authors, but might have contributed to the higher incidence of stroke in both younger and older women, the authors speculated.

LVADs were originally developed as a bridge to transplant (BTT) to support heart failure patients as they awaited heart transplantation, the therapy of choice. Eventually, their use was expanded to include patients who were not candidates for heart transplantation, i.e. destination therapy (DT), Najjar wrote.

CF-LVADs are second generation LVADs and "technological marvels that have revolutionized the care of patients with end-stage heart failure," wrote Najjar. Recent studies have shown that one year survival is 73% for those who receive their device as DT and 85% for those who receive the device as a BTT "which matches the one-year survival after heart transplantation," he said.

However, patients who receive CF-LVADS are still susceptible to bleeding events, due to the fact that patients often acquire von-Willebrand Syndrome, which results in reduced platelet activity and aggregation, and because they receive aspirin and warfarin. Stroke and pump thrombosis incidents are less common than bleeding, "however these are among the most serious events," the authors said.

Identification of risk factors, the authors wrote, "may help in the development of anticoagulation and anti-platelet strategies appropriately targeted to minimize events in these subgroups."

This study is the largest analysis of risk factors for bleeding, stroke and thrombosis, the authors said, noting that more trials are needed to establish whether prospectively targeting anticoagulation based on pre-operative risk factors reduces risk.

There were several limitations to this study. It was a retrospective analysis of a specific trial, and may not have been representative of the population as a whole. The study was not randomized or blinded. And events that took place in the immediate perioperative period and during the initial hospital stay were not evaluated, although they will be the subject of a separate analysis, the authors said.

Najjar provides research support for HeartWare Inc. and serves on their advisory board.

Boyle, is a consultant and receives honoraria from Thoratec Corporation. Jorde and Russell provide research and consulting support for Thoratec Corporation. Sun is a consultant for Thoratec Corporation. Park, Milano, and Frazier have received research and training grants from Thoratec Corporation. Sundareswaran and Farrar are employees of Thoratec Corporation.

Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner

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